Dental care product

ABSTRACT

A masticating strip useful in dental hygiene consisting of a cellular foam in which the surface cells incorporate longitudinal slits. The strips are sized to give a chewing volume of 1 to 4 cm 3  preferably about 3 cm 3 . The strips are made from a foam of a thermoplastic material selected from one or more of polyethylene (PE), polyvinyl acetate (PVA) or polyisobutylene. The strips may incorporate a dental adjuvant or a barrier material.

BACKGROUND TO THE INVENTION

It is known that chewing produces saliva which is a natural means ofremoving caries causing products from the teeth.

-   U.S. Pat. Nos. 5,114,704 and 6,178,922 disclose chewable products    for dog dental care.-   U.S. Pat. No. 5,133,971 proposes using a chewable membrane of    reconstituted cellulose.-   U.S. Pat. No. 4,554,154 discloses the use of a chewable tape    carrying an adhesive.-   U.S. Pat. No. 4,891,209 discloses a latex rubber masticating block    [chewing gum size] which is intended to inhibit caries.-   U.S. Pat. No. 5,939,049 discloses a chewing stick of jute or other    natural fibres. It is claimed to be an improvement in the natural    chewing sticks used by people in many developing countries.-   U.S. Pat. No. 6,123,982 discloses an expandable dental floss and    U.S. Pat. No. 6,039,054 to a dental floss having a foamed layer    around the core.-   Patent specification WO 00/32135 discloses a chewable foam strip of    PE or EVA.

The foam cells are closed and smaller than 1 mm in diameter.

A large proportion of caries infections occur in deep cracks andfissures which naturally occur in healthy teeth. There are three areasthat are subject to tooth decay, gum margins and between teeth as wellas inside pits and fissures. However brushing and flossing, mouth wash,toothpaste and chewing gum can only access and benefit the first 2areas. They cannot access inside pits and fissures where 80% of cavitiesoccur.

The prior attempts as disclosed in the patents mentioned above do noteffectively remove caries forming products from these deep cracks andfissures nor do they prevent those materials from entering the cracksand fissures. The only effective treatment of deep cracks and fissuresis to fill or seal them with a permanent barrier material whichoperation is performed by a dentist at a dental surgery. It is an objectof this invention to provide a product which prevents cariogenic foodproducts breaking down into caries producing acid inside these cracksand fissures as well as between teeth and at gum margins by removingthem.

BRIEF DESCRIPTION OF THE INVENTION

To this end the present invention provides a dental care strip of acellular foam in which the surface cells are open cup shaped cells. Thedental care strip can be used as dental floss or as a masticating stripto aid in cleaning teeth or delivering barrier materials to the cracksand fissures where caries most commonly commences.

This invention is predicated on the discovery that the deep cracks andfissures of teeth are not easily penetrated by saliva which is beingworked around by chewing gum or closed foam cells. The velocity of thesaliva is higher when the foam cells are broken but it takes some timechewing before a sufficient number of cells are broken. This process isexpedited by slitting the foam to provide outer cup shaped cells on eachfoam strip. Half open cells are not as effective as cup shaped cells inpropelling saliva with velocity into pits and fissures in the teeth.Preferably the foam cells are large and at least 1 mm in size.Preferably the foam sheet is slit diagonally across the thicknessbecause this not only provides the best shaped open cell to removeplaque and deliver saliva, but also provides a tapered edge that passesbetween the teeth more effectively. With this invention even 5 mm thickfoam strips can be compressed to pass between the teeth.

In assessing the efficacy of various materials to provide sufficientforce to the saliva to force it quickly into the deep cracks andfissures a glass model of a fissured tooth has been studied using fooddye to indicate penetration. This methodology has reduced the timeneeded to ascertaining if a procedure will benefit teeth from years(based on clinical trials) to a matter of hours.

Because the cells are cup shaped after being slit they quickly fill witha saliva mix which is forced out as the cup shaped cell is squeezedwhile chewing. This has been proved by the glass model of a fissure.Foam masticating strips as disclosed in specification WO 00/32135 do notallow sufficient penetration of the deep cracks and fissures within twoor three minutes of chewing. Even pin hole fracturing of the cells doesnot produce sufficient pumping action.

The masticating strips of this invention are sized to give a chewingvolume of 1 to 4 cm³ preferably about 2 cm³. The strips may be 50×20×2mm in dimension with 1 mm foam cells but preferably are 15×2×100 mm.

Any food grade plastic foam may be used including thermoplastics such aspolyethylene (PE), polyvinyl acetate (PVA) or polyisobutylene (PIB) toimprove cell size and provide thinner cell walls and provide a chewyfeel.

The foam strips of this invention may also be combined with barriermaterials that are able to penetrate the deep cracks and fissures withthe aid of the masticating strips of this invention. These barriermaterials are inert and prevent carbohydrate foods from entering thecracks and fissures and prevent the formation of the acids which causecaries. Suitable barrier materials include cocoa, cheese and finecalcium salt particles such as calcium carbonate combined with a carrierlike gelatin. It is preferred to use a foam strip that provides a shortacting bolus to deliver the barrier materials but not remove them.

To clean the teeth or to remove barrier materials the foam strips ofthis invention are formed into a long acting bolus.

DETAILED DESCRIPTION OF THE INVENTION

To assist with understanding this invention, reference will now be madeto the drawings in which:

FIG. 1. illustrates a strip of foam of this invention;

FIG. 2. illustrate a glass model which simulates a fissure in a tooth;

FIGS. 3, 4, 5, 6 and 7. illustrate a fissure at one end of the glassmodel in FIG. 2. subjected to various foodstuffs and treatments;

FIGS. 8 a and 8 b. illustrate a food product which incorporates a dentalstrip of this invention;

FIGS. 9 aand 9 b. illustrate another product configuration;

FIG. 10 illustrates another package utilizing the foam of thisinvention;

FIG. 11 illustrates another package utilizing the foam of thisinvention.

FIG. 12 illustrates a conventional wrapped confection incorporating thefoam of this invention.

A strip of foam of this invention as shown in FIG. 1 is 2 mm×15 mm×100mm which creates a long acting chewy bolus volume of about 3 cm³

The glass model illustrated in FIG. 2 consists of two strips of glassabout 5 mm thick and 20 mm wide and about 60 mm long, stuck togetherwith white silicone in an H fashion or clipped together with a thinTeflon gasket. This leaves a very thin pocket or envelope open at eachend as in FIG. 2, replicating the actions observed inside pits andfissures. One end is forced into food or other material and saliva orwater usually with a dye to clearly show if the food or other materialsaliva or water mix is forced inside the fissure by the mix texture orconsistency. Suitable fibre added to the mix greatly improvespenetration inside pits and fissures and identifies if a stable short orlong acting bolus is suitable to fill the pocket as illustrated in FIG.3. Not every fibre or long acting bolus will force saliva etc inside thefissure. Chewing gum is a long acting bolus, which does not absorb andexpel the fluids or mixtures and cannot remove material or dye from themodel. FIG. 4 illustrates the results of brushing or chewing gum inpenetrating and removing food particles in cracks and fissures and itcan be seen that these have little effect. In contrast the foams of thisinvention provide complete penetration in a short time as illustrated inFIG. 5. when cheeses is applied to the glass model as illustrated inFIG. 6 cheese penetrates and seals the fissure. When normal food isapplied to the glass model the results as illustrated in FIG. 7demonstrate that it is difficult to remove.

The masticating dental foam of this invention may be made as follows:

Polyethylene pellets are melted in an extruder with a fine nucleatingpowder such as flower of fluoride. 2% polyisobutylene and a foamingagent such as butane propane, natural gas or carbon dioxide are pumpedinto the melt under controlled pressure to foam the mass as it exits theextruder die. This forms large numbers of interlinked fine wall cells.The pressure should be close to the cell bursting pressure to facilitatecreating a soft chewy foam. The foamed sheet may be surface treated witha wire roller or slitting blades to open the foam cells with slits.Preferably the foam exits the die as a tubular sheet about 10 or 20 mmthick most preferably 15 mm thick and is then slit vertically intostrips 2 or 3 mm thick. Slitting on an angle through the thickness is apossible alternative as it not only provides cup cells on the cutsurface but improves ease of passing between teeth. Preferably thestrips are rectangular 15 mm by 50 or 100 mm and 2 mm thick.

Another variation provided by this invention is V shaped strip in whichthe foam is not fully slit so that two strips are joined at one edge andthe V shaped strip may be used to envelop the teeth.

A short acting bolus can be created with 5 mm cube foam blocks formedinto jubes with a suitable barrier material. The addition of smallamounts of polyisobutylene to the foam improves the foam by formingbigger cells and the foam is more chewy and is slightly tacky. Gelatinand PIB are used to prevent dehydration of the barrier material on thefoam strips. The PE foam strips of this invention act as a bulkingcarrier that can run through a gelatin dip at much higher speeds than asindividual units and the coated strands pass up and down a drying,cooling setting tower before being cut and packed.

When slit, the cells provide a cup like surface that can hold saliva oran additive that is easy to force into pits and fissures immediatelywhich is not possible with the smooth surface of a closed cell foam oreven with punctured cells which close over under pressure. The exposedslit cell edges of this invention are also more efficient at plaque andfood removal, cutting into and holding the plaque or food rather thansliding over it. Even square 5 mm thick foam can be compressed so as topass between the teeth while applying a slight orthodontic pressure thatas well as clean teeth could aid jaw growth and help prevent crowdedteeth.

Suitable dental agents such as one mg of fluoride may be incorporatedinside the cells of each unit of dental foam to give 5 ppm Fluoride ionin the saliva for about 10 minutes after eating and perhaps before bed.It is desirable not to eat anything for about two hours after chewingthe long acting fibre bolus to ensure complete remineralisation so theideal time for mineralisation with fluoride is before going to bed. Thisdosage is about 5 kilos of powdered NaF per ton of PE added at thehopper of the extruder as a nucleating agent giving about 30 billioncells in 15,000,000 units of dental foam. It is unlikely that therecommended dose of 1 mg of fluoride per day would be exceeded.

Additives may be applied to the foam by dipping or spraying before thefoam is cut into strips as long as the open cells hold the additive.

The foam strip of this invention can be presented for use in a varietyof ways. FIGS. 8A and B show two foam strips sealing a barrier food withtwo side tags. The side tags which are dental strips of this inventionmay be torn off and used after eating to remove food and neutraliseacid. The dental strips of this invention which enclose the barrier foodis chewed prior to the meals to seal the cracks and fissures with abarrier material such as cheese. A similar product is illustrated inFIGS. 9A and 9B in which the a barrier food is enclosed within a foamtube according to this invention with two dependent tags that can betorn off and used after eating to remove food.

The foam material of this invention can itself be used as a packagingmaterial for foods or confections that can be used for cleaning teethafter the package is opened. FIG. 10 depicts two strips of foam used topack and seal a confection or snack.

FIG. 11. Shows two strips of foam used to pack and seal a largeconfection or multiple units of the chewy device. As many as 50 unitscan be packed in this way to fit an average business envelope and daypacks can be cut from this small bulk pack to serve as both barriersnacks before eating and cleaning device or gum after eating. The endsections of the pack can be used as reusable envelopes to carry a daysupply of barrier snacks and cleaning devices even with a preferredtoothpaste added.

Alternatively the dental strip of this invention can be combined withthe wrapper of a confection as shown in FIG. 12 where a sweet 22 isenclosed in a conventional wrapping 20 and the foam 21 of this inventionis also included. After eating the sweet the foam can be chewed so thatthe saliva generated by chewing the foam flushes the cracks and fissuresof the teeth.

From the above it can be seen that this invention provides an effectivedental hygiene material that is convenient to use at any timeparticularly prior to and after eating. Those skilled in the art willrealize that the invention can be applied to a variety of applicationsand the size and volume of the masticating strips can vbe varied asdesired. The dental adjuvants that are incorporated into the cells orapplied to the surface of the strips may be chosen from among the widerange of materials currently available. Similarly other methods ofmanufacturing the slit cell foam strips may be employed.

1. A dental care masticating strip comprising a thermoplastic polymericcellular foam having a total volume of 1 to 4 cubic centimeters thestrip having on its surface open cup shaped cells of about 1 mm indiameter.
 2. A dental care strip as claimed in claim 1 in whichthermoplastic cellular foam material is selected from one or more ofpolyethylene (PE), polyvinyl acetate (PVA) or polyisobutylene.
 3. Adental care strip of a cellular foam in which the surface cells are opencup shaped cells.
 4. A dental care strip as claimed in claim 3 in whichthe foam cells are at least 1 mm in diameter.
 5. A dental care strip asclaimed in claim 3 sized to give a chewing volume of 1 to 4 cm³preferably about 3 cm³.
 6. A dental care strip as claimed in claim 3 inwhich the strip is formed form a foam sheet by slitting diagonallyacross the thickness of the foam sheet.
 7. A dental care strip asclaimed in claim 3 which is made from a foam of a thermoplastic materialselected from one or more of polyethylene (PE), polyvinyl acetate (PVA)or polyisobutylene.
 8. A dental care strip according claim 1 which alsoincorporates a dental adjuvant or a barrier material.
 9. A dental carestrip and barrier material as claimed in claim 8 that provides a shortacting bolus to deliver the barrier material to deep cracks and fissuresin the teeth.
 10. A dental care strip as claimed in claim 8 in which thebarrier material is a calcium salt, cheese or cocoa powder.
 11. A dentalcare strip as claimed in claim 3 which forms a long acting bolus toremove materials in the deep cracks and fissures of the teeth.